In general, a system for driving a motor may include a power storage device (for example, a battery), an inverter for converting DC power stored in the power storage device into three-phase AC power for driving the motor, the motor, and a controller for controlling switching of an inverter based on a current command, generated based on a torque command for driving the motor, and actually measured current, provided to the actual motor.
The inverter may include a plurality of switching elements, and generate AC power by controlling the switching elements in a Pulse Width Modulation (PWM) type. The AC power, generated by the inverter, is provided to the motor and thus the motor operates.
When the pulse width modulation signal for controlling the switching elements within the inverter has a fixed frequency, the control may be simplified and thus controllability may be excellent and the motor driving system may be generally stably controlled. However, when the inverter is controlled by the pulse width modulation signal having the fixed frequency, a strong high frequency component appears in a band corresponding to an integer multiple of the switching frequency and electronic noise and vibration may occur.
In order to solve the disadvantage of the pulse width modulation signal having the fixed switching frequency, a Random Pulse Width Modulation (RPWM) scheme of instantaneously distributing the switching frequency band has been known. When the random pulse width modulation scheme is applied, noise or vibration may be suppressed through energy distribution but the switching frequency may be randomly changed, so that controllability may deteriorate.
The matters which have been described as the technology corresponding to the background of the present disclosure are only for assisting with an understanding of the background of the present disclosure, and should not be considered as the prior art already known to those skilled in the art.